Leishmaniasis In Endemic Area Research Articles

From Mud and Stick-walled Houses to Corrugated Iron sheet Houses: A New Strategy for Preventing Human-Vector Contact in Marigat Sub-county a Leishmaniasis-endemic Area in Kenya

Department of Technical and Applied Biology, Technical University of Kenya, Kenya 2 Department of Science and Health, Daystar University, Kenya 3 Centre for Biotechnology, Research and Development, Leishmaniasis Laboratory, Kenya Medical Research Institute, Kenya

Pharmacovigilance of Miltefosine in Treatment of Visceral Leishmaniasis in Endemic Areas of Bihar, India.

Miltefosine, the only oral drug for visceral leishmaniasis (VL), is being used as the first-line drug under the VL elimination program in the Indian subcontinent. Miltefosine is an oral drug which was used as a topical application for skin metastasis of breast cancer. It was found to be effective against Leishmania donovani The main adverse events (AE) reported previously with miltefosine use includes diarrhea, vomiting, and dehydration. Other AEs include, raised serum alanine transaminase/aspartate aminotransferase and renal parameters such as creatinine. In this study, we report AEs in a large patient cohort of VL treated with miltefosine. The purpose of this pharmacovigilance study was to assess adverse drug reactions (ADRs)/AE of miltefosine treatment under unrestricted condition in the field setup. Patients were followed up to 6 months for therapeutic effectiveness. Outcomes of a larger data set of patients treated with this regimen from April 2012 to March 2015 were recorded. In the present study, 646 patients of VL were given miltefosine. Majority of the study subjects (58%) were male. Relapse occurred in 7% during follow-up period. Main causes of death were VL-pulmonary tuberculosis coinfection, extreme diarrhea, and acute pancreatitis which were reported in 1.7% subjects. Of 553 (85.6%) patients completing full course of treatment, 463 (83.7%) showed ADR with miltefosine during the study period. About 2.3% were suffering severe ADR, 51% from moderate, and the rest had mild ADR. The initial and final cure rate was 97.4% and 85.6%, respectively.

Aspects on the Ecology of Phlebotomine Sand Flies (Diptera: Psychodidae) From Guaraí, State of Tocantins, Brazil, Endemic Area for American Cutaneous Leishmaniasis

In Brazil, American cutaneous leishmaniasis (ACL) ecology involves a diversity of Leishmania species transmitted by different sand fly species. Workers involved in agricultural activities are those mainly affected by ACL in some regions from Tocantins State (TO), Brazil, where the disease can be established in new settlements. The objective of this study was to examine the seasonal and hourly frequency of sand fly species, focusing on the potential vectors of ACL, in a settlement in Guaraí (TO), an ACL transmission area. Sand flies were captured in forested area close to Pedra Branca Agricultural Project settlement, from March 2006 until December 2007, using Shannon trap. Monthly captures were made from 06:00 p.m. to 10:00 p.m., and 24-h captures were done twice per semester, from 06:00 a.m. to 06:00 a.m. A total of 10,089 specimens from 30 species were identified. Psychodopygus complexus Mangabeira, Psychodopygus llanosmartinsi Fraiha & Ward, and Nyssomyia antunesi Coutinho were the most abundant species. Nyssomyia antunesi was more frequent during the dry period, whereas Ps. complexus and Ps. llanosmartinsi had high frequencies during the rainy season. Precipitation was positively correlated with Ps. complexus and Ps. llanosmartinsi abundance, and negatively correlated with Ny. antunesi During 24-h captures, the majority of specimens were captured during the night followed by a decrease at dawn. The behavior and previous finding of natural infection by Leishmania (Viannia) braziliensis of Ps. complexus led us to the conclusion that this species can be a potential vector of L. (V.) braziliensis during the rainy season in Guaraí.

Canine cutaneous leishmaniasis by Leishmania (Viannia) braziliensis in an agricultural settlement, endemic area for leishmaniasis

ABSTRACT Cutaneous leishmaniasis has several species of Leishmania as agents, and a wide variety of wild and domestic animals as hosts and different species of phlebotomines as vectors. A case of cutaneous leishmaniasis in a dog coming from an agricultural settlement is described. This is the first report of parasitism in a dog by Le. (Viannia) braziliensis in Mato Grosso do Sul State. Attention is called to the importance of including this protozoonosis in the differential diagnosis of dermopathies in dogs as also the need to assess the importance of the domestic dog as a possible reservoir of Le. braziliensis.

Molecular and Serological Evidence of Leishmania Infection in Stray Dogs from Visceral Leishmaniasis–Endemic Areas of Bangladesh

Visceral leishmaniasis (VL), or kala-azar, is mainly caused by two closely related Leishmania species, Leishmania infantum and Leishmania donovani Leishmania infantum is responsible for zoonotic VL, with dogs as the main reservoir host in the Mediterranean, the Middle East, Asia, and South America. In the Indian subcontinent, VL is caused by L. donovani and is considered anthroponotic, although the only known vector, the sand fly, is zoophilic in nature. The role of domestic and stray dogs in VL transmission is still unclear in this area. We screened 50 stray dogs from VL-endemic areas of Bangladesh for serological and molecular evidence of Leishmania infection. We detected anti-Leishmania antibodies in six (12%) dog serum samples using rK39 immunochromatographic tests. We observed Leishmania kinetoplast DNA in 10 (20%) buffy coat DNA samples by real-time polymerase chain reaction (PCR), five of which were positive based on internal transcribed spacer 1-PCR. A sequencing analysis of the amplified products confirmed that the parasitic DNA was derived from L. donovani Our findings support the hypothesis that stray dogs are an animal reservoir for L. donovani in this endemic region. Further studies are required to determine the precise role of dogs in the epidemiology of VL in Bangladesh.

Environmental parameters as risk factors for human and canine Leishmania infection in Thessaly, Central Greece.

Thessaly, Central Greece, is an endemic area for leishmaniasis with higher incidence rate during the last years. We herein investigated the geographical distribution of human leishmaniasis cases and Leishmania infected dogs in relation to environmental parameters to identify high-risk areas. All the human leishmaniasis cases (n = 82) reported to Hellenic Centre for Disease Control and Prevention from 2007 to 2014 and 85 Leishmania polymerase chain reaction positive dogs were included in this study. To analyse the data geographical information system (GIS) together with the Ecological Niche Model (ENM) were used. The most important findings of the study were: (i) Central plain of Thessaly together with the coast line and the western and eastern lowlands were identified as high-risk geographical areas. (ii) The highest percentage of the high-risk areas was found in low altitude (<200 m above sea level) and in irrigated and cultivated agricultural areas. (iii) A total of 20% of the human settlements was found in high-risk areas. (iv) The maximum temperature of the warmest month contributes the highest per cent to define both environmental niche profiles for humans and dogs. (v) The ENM could be a useful tool for the epidemiological study of leishmaniasis. Spatial analysis may allow the design of entomological studies and identify target population in order to implement preventive measures.

Community knowledge, attitude and practice towards cutaneous leishmaniasis endemic area Ochello, Gamo Gofa Zone, South Ethiopia

ObjectiveTo assess the knowledge, attitude and practice of the community related to cutaneous leishmaniasis (CL) in an endemic area Ochello, Gamo Gofa Zone, South Ethiopia. MethodsWe conducted community based cross-sectional survey among residents in Ochello from November to December 2014. The study area was purposely selected based on previous reports on endemicity of CL. Using simple random sampling technique, a total of 392 household participants were selected in the study area Ochello. Structured questionnaire was used to collect the data. Regarding the responses given to knowledge, attitude and practice, a score of 1 was given for each right response and 0 for unsure responses. Data were double entered and analysis was conducted using SPSS version 20 statistical software. Descriptive statistics that include frequency and percentage were used to analyze the results. ResultsIn total, 392 individuals were participated in our study where 225 (57.4%) of the participants were males and 167 (42.6%) were females. Of all the total participants, 265 (67.6%) had heard of the disease, and 127 (32.4%) responded that they did not know CL. Based on the scoring results, 265 (67.6%) participants were knowledgeable about CL. Out of 265 participants who heard about CL, most of them [215 (54.8%)] had the attitude that CL was a problem in their area and had no positive attitude towards the treatment of CL. Approximately, 215 (54.8%) replied that CL was preventable. Majority of the respondents did not sleep outdoors and did not practice sleeping near vegetation with or without bed net. ConclusionsThe current finding indicated that the inhabitants of Ochello developed good awareness and encouraging attitude regarding CL. However, their prevention and control practice was very low. Hence, the result of this study calls for organized community awareness creation through various means.

Genomic and Molecular Characterization of Miltefosine Resistance in Leishmania infantum Strains with Either Natural or Acquired Resistance through Experimental Selection of Intracellular Amastigotes.

During the last decade miltefosine (MIL) has been used as first-line treatment for visceral leishmaniasis in endemic areas with antimonial resistance, but a decline in clinical effectiveness is now being reported. While only two MIL-resistant Leishmania infantum strains from HIV co-infected patients have been documented, phenotypic MIL-resistance for L. donovani has not yet been identified in the laboratory. Hence, a better understanding of the factors contributing to increased MIL-treatment failure is necessary. Given the paucity of defined MIL-resistant L. donovani clinical isolates, this study used an experimental amastigote-selected MIL-resistant L. infantum isolate (LEM3323). In-depth exploration of the MIL-resistant phenotype was performed by coupling genomic with phenotypic data to gain insight into gene function and the mutant phenotype. A naturally MIL-resistant L. infantum clinical isolate (LEM5159) was included to compare both datasets. Phenotypically, resistance was evaluated by determining intracellular amastigote susceptibility in vitro and actual MIL-uptake. Genomic analysis provided supportive evidence that the resistance selection model on intracellular amastigotes can be a good proxy for the in vivo field situation since both resistant strains showed mutations in the same inward transporter system responsible for the acquired MIL-resistant phenotype. In line with previous literature findings in promastigotes, our data confirm a defective import machinery through inactivation of the LiMT/LiRos3 protein complex as the main mechanism for MIL-resistance also in intracellular amastigotes. Whole genome sequencing analysis of LEM3323 revealed a 2 base pair deletion in the LiMT gene that led to the formation an early stop codon and a truncation of the LiMT protein. Interestingly, LEM5159 revealed mutations in both the LiMT and LiRos3 genes, resulting in an aberrant expression of the LiMT protein. To verify that these mutations were indeed accountable for the acquired resistance, transfection experiments were performed to re-establish MIL-susceptibility. In LEM3323, susceptibility was restored upon expression of a LiMT wild-type gene, whereas the MIL-susceptibility of LEM5159 could be reversed after expression of the LiRos3 wild-type gene. The aberrant expression profile of the LiMT protein could be restored upon rescue of the LiRos3 gene both in the LEM5159 clinical isolate and a ΔLiRos3 strain, showing that expression of LdMT is dependent on LdRos3 expression. The present findings clearly corroborate the pivotal role of the LiMT/LiRos3 complex in resistance towards MIL.

Xenodiagnosis on dogs with visceral leishmaniasis: Canine and sand fly aspects related to the parasite transmission

One of the main limitations for the effective control of canine leishmaniasis in endemic areas is the difficulty in identifying infectious dogs. The objective of this study was to determine factors, related to dogs and to parasite detection in sand flies, which are associated with the positive xenodiagnosis of Leishmania infantum using the vector Lutzomyia longipalpis. The xenodiagnosis was performed in 50 owned dogs residing in endemic areas, which were divided into three different groups: G1—26 dogs proved to be infected and classified by severity of VL clinical signs on physical examination; G2—15 dogs proved to be infected and classified by severity of clinical signs and intensity of laboratory abnormalities; G3—nine dogs that were seropositive for anti-Leishmania IgG in ELISA tests. Parasite search in the sand flies after having fed on dogs in the xenodiagnosis was performed by both methodologies, PCR and dissection followed by microscopy. In G1, 58% (15/26) of dogs were able to transmit Leishmania to the vector, when parasite detection in sand flies were performed by PCR technique, 5 days after blood meal, whereas in G2, 53% (8/15) transmitted the parasite to the vector, however, confirmation was performed by direct observation of parasite through optical miscroscopy held 10 days after blood meal. Rate of infectiousness of dogs to sand flies was positively associated to severity of disease (p=0.042 and p=0.040), regardless the method used for clinical classification or for parasite detection in sand flies after xenodiagnosis. In G1 30% (3/10) of dogs with subclinical infection were infectious to the vector, while 80% (12/16) of dogs with clinical disease were also infectious. Even more, 17% (1/6) of dogs that had moderate disease were infectious to the sand flies, while 78% (7/9) of dogs with severe disease were infectious in G2. Still in G2, the proportion of sand flies infected (grade of infectiousness) was significantly lower (p=0.0098) when they fed on dogs with moderate disease (1%) in comparison with dogs with severe disease (38%). The dogs from G3 presented a rate of infectiousness of 11% (1/9), demonstrating that the indirect ELISA is not a good indicator of infectiousness and, therefore, should not be used as a confirmatory test for the euthanasia of dogs, as it is currently done in Brazil.

Association of interleukin-18 gene polymorphism with susceptibility to visceral leishmaniasis in endemic area of Bihar, an Indian population

Interleukin-18 (IL-18) is a cytokine that mediates Th1 response by inducing interferon-gamma (IFN-γ) production in T cells and natural killer cells. Genetic polymorphisms in the IL-18 gene have been found to be associated with its expression in cancer, tuberculosis, HBV infection, and various other diseases. Lower plasma level of IL-18 in visceral leishmaniasis (VL) patients might be associated with polymorphisms in the regulating or coding region of the gene. Three single nucleotide polymorphisms (SNPs), rs1946519 (-656 G/T) and rs187238 (-137 G/C) in the promoter region and rs549908 (+105 A/C) in the codon region, were genotyped in 204 parasitological confirmed VL patients and 267 controls with no past history of VL. For each locus, polymerase chain reaction (PCR) followed by restriction digestion was performed. IL-18 expression in peripheral blood mononuclear cells (PBMC) collected from VL patients and controls was measured by quantitative real-time RT-PCR. Distribution of G allele at position -656 (P < 0.0001) and double haplotypes GGC/GGA (P = 0.05) were found to be significantly associated with controls while genotypes TT (P < 0.0001) and single haplotypes TGA (P = 0.0002), with cases. The inheritance of G allele at the position -656 might be considered as a protective allele for VL.

Prevalence and Associated Factors of Canine Visceral Leishmaniasis in an Endemic Area of Mato Grosso, Brazil

Background: Canine visceral leishmaniasis is a chronic and severe disease of great interest to global public health. In Brazil, the main species causing visceral leishmaniasis is Leishmania chagasi [syn. Leishmania infantum], which is transmitted by sandflies of the species Lutzomyia longipalpis and Lu. cruzi. This study aimed to determine the risk factors and prevalence of visceral leishmaniasis in dogs residing in endemic areas of the municipality of Várzea Grande, Mato Grosso.Material, Methods &amp; Results: The study was conducted in the Várzea Grande neighbourhoods Jardim Eldorado, Parque Sabiá and São Mateus, which are located in the Brazilian Cerrado region and are endemic for visceral leishmaniasis. The Várzea Grande is a mostly commercial and industrial municipality and relies on subsistence farming. To describe the general characteristics of the dog population and housing environment, an interview was carried out with the dog owners in each household. This interview addressed local demographics and the identification of dogs to establish epidemiological aspects of canine illness and risk factors for infection. The dogs were examined and physically restrained for blood collection by jugular venipuncture. For serological testing, a commercial enzyme-linked immunosorbent assay (ELISA) was used. A Chi-square test or Fisher’s exact test was used to identify associations between independent variables and the seroprevalence of dogs with anti-Leishmania antibodies. It were collected blood from 521 animals, including 160 belonging to Jardim Eldorado, 129 to Parque Sabiá and 232 to São Mateus. Of these animals, 120 were reactive by ELISA, with a prevalence of 23.0%. There was no statistically significant difference (P &gt; 0.05) according to gender, age, racial definition, origin, time with family, presence of ectoparasites, or the presence of people with skin wounds at home or on other pets. The major risk factor for canine infection was fur length; dogs with short fur were 2.2 times more likely to be infected than dogs with long fur.Discussion: The prevalence of canine leishmaniasis in endemic areas was found to be similar to studies in Cuiaba, a city in Várzea Grande, which also included neighbourhoods endemic for visceral leishmaniasis as study areas. Other studies have shown prevalence rates that differ from those found in this study. This difference may either be because the neighbourhoods in this study had already experienced outbreaks of the disease or because serum samples were cross-reactive with other trypanosomatids. While infection was more readily detected in dogs with clinical signs, asymptomatic dogs with anti-Leishmania antibodies were found in greater numbers, which is consistent with the literature. Hair length was the only factor associated with canine leishmaniasis in this study; short-haired animals were most at risk of contracting the disease because they had more skin exposure to sandflies during blood feeding. In conclusion, endemic districts of Várzea Grande had high prevalence rates of canine visceral leishmaniasis, and a short length coat was associated with infection.

SAND FLIES (DIPTERA: PSYCHODIDAE) IN AN ENDEMIC AREA OF LEISHMANIASIS IN AQUIDAUANA MUNICIPALITY, PANTANAL OF MATO GROSSO DO SUL , BRAZIL.

SUMMARYThe Aquidauana municipality is considered an endemic area of leishmaniasis and an important tourist site in Mato Grosso do Sul State. The aim of this study was to investigate the sand fly fauna in the city of Aquidauana. Captures were carried out twice a month, from April 2012 to March 2014 with automatic light traps and active aspiration, in the peridomicile and domicile of six residences. A total of 9,338 specimens were collected, 3,179 and 6,159 using light traps and active aspiration, respectively. The fauna consisted of: Brumptomyia brumpti, Evandromyia aldafalcaoae, Ev. evandroi, Ev. lenti, Ev. orcyi, Ev. sallesi, Ev. termitophila, Ev. walkeri, Lutzomyia longipalpis and Psathyromyia bigeniculata. The most abundant species captured was Lutzomyia longipalpis, present in all the ecotopes, predominantly in peridomicile areas, and mainly males. Leishmania DNA was not detected in the insects. It was observed the abundance of the sand fly fauna in the region, as well as the high frequency of Lu. longipalpis, the main vector of L. infantum. The results of this study show the need to increase the monitoring and more effective control measures. It is noteworthy that the studied region presents several activities related to tourism and recreation, increasing the risk of transmission of leishmaniasis to this particular human population.

Age structure of owned dogs under compulsory culling in a visceral leishmaniasis endemic area.

The age structure of the dog population is essential for planning and evaluating control programs for zoonotic diseases. We analyzed data of an owned-dog census in order to characterize, for the first time, the structure of a dog population under compulsory culling in a visceral leishmaniasis endemic area (Panorama, São Paulo State, Brazil) that recorded a dog-culling rate of 28% in the year of the study. Data on 1,329 households and 1,671 owned dogs revealed an owned dog:human ratio of 1:7. The mean age of dogs was estimated at 1.73 years; the age pyramid indicated high birth and mortality rates at the first year of age with an estimated cumulative mortality of 78% at the third year of age and expected life span of 2.75 years. In spite of the high mortality, a growth projection simulation suggested that the population has potential to grow in a logarithmic scale over the years. The estimated parameters can be further applied in models to maximize the impact and minimize financial inputs of visceral leishmaniasis control measures.

Molecular detection and identification of Leishmania spp. in naturally infected Phlebotomus tobbi and Sergentomyia dentata in a focus of human and canine leishmaniasis in western Turkey

Human visceral leishmaniasis (VL) is reported from 38 provinces of Turkey and dogs are accepted as main reservoir hosts. Kuşadası town, belonging to Aydın province and located in western part of Turkey, is endemic for human and canine visceral leishmaniasis caused by Leishmania infantum MON1 and MON98.In this study, phlebotomine survey was conducted to determine the vector sand fly species and to identify sand fly blood meal sources. In August and September 2012, 1027 sand fly specimens were caught using CDC light traps. Eight Phlebotomus and two Sergentomyia species with the dominancy of Phlebotomus tobbi (61.34%) were detected. A total of 622 female sand flies (571 Phlebotomus; 51 Sergentomyia) were checked for Leishmania infection by direct dissection of the midgut. The half of the midgut content was inoculated into NNN culture for isolation of the parasite. Leishmania species-specific ITS1 real time PCR, conventional PCR assays of ITS1 and hsp70 genes and subsequent sequencing were performed from extracted DNAs. A region of cytochrome b (cyt-b) gene of vertebrates based PCR was used to determine the source of blood meal of sand flies.In microscopical examinations, two female specimens (0.32%) were found naturally infected with high number and different stages of promastigotes. No growth was observed in NNN culture but Leishmania DNA was obtained from both specimens. First positive specimen was identified as P. tobbi and L. infantum DNA was detected. Second specimen was Sergentomyia dentata, but Leishmania DNA could not be identified on species level. A total of 16 blood-fed female P. tobbi specimens were used for blood meal analysis and eight, three and one specimens were positive for human, dog and mouse, respectively.This is the first detection of Leishmania promastigotes using microscopical examination in P. tobbi and S. dentata in human and canine visceral leishmaniasis endemic area in western part of Turkey. Our results indicate that, (i) P. tobbi is the principal vector species and (ii) human and dogs are main blood sources. The detection of Leishmania sp. in Sergentomyia species may be an evidence for natural cycle of Sauro-leishmania agents in the area.

Intradomiciliary and peridomiciliary captures of sand flies (Diptera: Psychodidae) in the leishmaniasis endemic area of Chapare province, tropic of Cochabamba, Bolivia

In South America, cutaneous leishmaniasis is the most frequent clinical form of leishmaniasis. Bolivia is one of the countries with higher incidence, with 33 cases per 100,000 individuals, and the disease is endemic in 70% of the territory. In the last decade, the number of cases has increased, the age range has expanded, affecting children under 5 years old, and a similar frequency between men and women is found. An entomological study with CDC light traps was conducted in three localities (Chipiriri, Santa Elena and Pedro Domingo Murillo) of the municipality of Villa Tunari, one of the main towns in the Chapare province (Department of Cochabamba, Bolivia). A total of 16 specimens belonging to 6 species of the genus Lutzomyia were captured: Lu. aragaoi, Lu. andersoni, Lu. antunesi, Lu. shawi, Lu. yuilli yuilli and Lu. auraensis. Our results showed the presence of two incriminated vectors of leishmaniasis in an urbanized area and in the intradomicile. More entomological studies are required in the Chapare province to confirm the role of vector sand flies, the intradomiciliary transmission of the disease and the presence of autochthonous cases of cutaneous leishmaniasis.

Evaluation of two recombinant Leishmania proteins identified by an immunoproteomic approach as tools for the serodiagnosis of canine visceral and human tegumentary leishmaniasis

Serological diagnostic tests for canine and human leishmaniasis present problems related with their sensitivity and/or specificity. Recently, an immunoproteomic approach performed with Leishmania infantum proteins identified new parasite antigens. In the present study, the diagnostic properties of two of these proteins, cytochrome c oxidase and IgE-dependent histamine-releasing factor, were evaluated for the serodiagnosis of canine visceral (CVL) and human tegumentary (HTL) leishmaniasis. For the CVL diagnosis, sera samples from non-infected dogs living in an endemic or non-endemic area of leishmaniasis, sera from asymptomatic or symptomatic visceral leishmaniasis (VL) dogs, from Leish-Tec®-vaccinated dogs, and sera from animals experimentally infected by Trypanosoma cruzi or Ehrlichia canis were used. For the HTL diagnosis, sera from non-infected subjects living in an endemic area of leishmaniasis, sera from active cutaneous or mucosal leishmaniasis patients, as well as those from T. cruzi-infected patients were employed. ELISA assays using the recombinant proteins showed both sensitivity and specificity values of 100% for the serodiagnosis of both forms of disease, with high positive and negative predictive values, showing better diagnostic properties than the parasite recombinant A2 protein or a soluble Leishmania antigen extract. In this context, the two new recombinant proteins could be considered to be used in the serodiagnosis of CVL and HTL.

A rapid molecular diagnosis of cutaneous leishmaniasis by colorimetric malachite green-loop-mediated isothermal amplification (LAMP) combined with an FTA card as a direct sampling tool

Leishmaniasis remains one of the world’s most neglected diseases, and early detection of the infectious agent, especially in developing countries, will require a simple and rapid test. In this study, we established a quick, one-step, single-tube, highly sensitive loop-mediated isothermal amplification (LAMP) assay for rapid detection of Leishmania DNA from tissue materials spotted on an FTA card. An FTA-LAMP with pre-added malachite green was performed at 64°C for 60min using a heating block and/or water bath and DNA amplification was detected immediately after incubation. The LAMP assay had high detection sensitivity down to a level of 0.01 parasites per μl. The field- and clinic-applicability of the colorimetric FTA-LAMP assay was demonstrated with 122 clinical samples collected from patients suspected of having cutaneous leishmaniasis in Peru, from which 71 positives were detected. The LAMP assay in combination with an FTA card described here is rapid and sensitive, as well as simple to perform, and has great potential usefulness for diagnosis and surveillance of leishmaniasis in endemic areas.

A Leishmania-specific hypothetical protein expressed in both promastigote and amastigote stages of Leishmania infantum employed for the serodiagnosis of, and as a vaccine candidate against, visceral leishmaniasis.

BackgroundLiHyV is an antigenic hypothetical protein present in both promastigote and amastigote stages of Leishmania infantum, which was recently identified by an immunoproteomic approach. A recombinant version of this protein (rLiHyV) was evaluated as a diagnostic marker for canine VL (CVL). In addition, the prophylactic efficacy of the rLiHyV protein, and two of its CD8+ T cell epitopes, has been analyzed in a murine model of visceral leishmaniasis (VL).MethodsInitially, the rLiHyV protein was evaluated by an ELISA technique for the serodiagnosis of CVL. Secondly, vaccines composed of the recombinant protein and both chemically synthesized peptides, combined with saponin as an adjuvant; were administered subcutaneously into BALB/c mice. The cellular and humoral responses generated by vaccination were evaluated. In addition, the parasite burden and immune response were studied 10 weeks after L. infantum infection.ResultsThe rLiHyV protein was recognized by antibodies of VL dogs. No cross-reactivity was obtained with sera from dogs vaccinated with a Brazilian commercial vaccine, with sera from animals infected with Trypanosoma cruzi, Babesia canis and Ehrlichia canis, or those from non-infected animals living in an endemic area for leishmaniasis. After challenge with L. infantum, spleen cells of BALB/c mice vaccinated with rLiHyV/saponin stimulated with parasite antigens showed a higher production of IFN-γ, IL-12 and GM-CSF, than the same cells obtained from mice vaccinated with the individual peptides, or mice from control (inoculated with saline or saponin) groups. This Th1-type cellular response observed in rLiHyV/saponin vaccinated mice was accompanied by the induction of parasite-specific IgG2a isotype antibodies. Animals immunized with rLiHyV/saponin showed significant reductions in the parasite burden in the liver, spleen, bone marrow and in the lymph nodes draining the paws relative to control mice.ConclusionsThe present study showed for the first time that the L. infantum LiHyV protein could be considered as a vaccine candidate against L. infantum infection, as well as a diagnostic marker for CVL.

Canine Antibodies against Salivary Recombinant Proteins of Phlebotomus perniciosus: A Longitudinal Study in an Endemic Focus of Canine Leishmaniasis.

BackgroundPhlebotomine sand flies are vectors of Leishmania parasites. During blood feeding, sand flies deposit into the host skin immunogenic salivary proteins which elicit specific antibody responses. These anti-saliva antibodies enable an estimate of the host exposure to sand flies and, in leishmaniasis endemic areas, also the risk for Leishmania infections. However, the use of whole salivary gland homogenates as antigen has several limitations, and therefore, recombinant salivary proteins have been tested to replace them in antibody detection assays. In this study, we have used for the first time sand fly salivary recombinant proteins in a longitudinal field study on dogs.Methodology/Principal FindingsSera from dogs naturally exposed to P. perniciosus bites over two consecutive transmission seasons in a site endemic for canine leishmaniasis (CanL) were tested at different time points by ELISA for the antibodies recognizing whole saliva, single salivary 43 kDa yellow-related recombinant protein (rSP03B), and a combination of two salivary recombinant proteins, 43 kDa yellow-related protein and 35.5 kDa apyrase (rSP01). Dogs were also tested for Leishmania infantum positivity by serology, culture, and PCR and the infection status was evaluated prospectively. We found a significant association between active CanL infection and the amount of anti-P. perniciosus saliva antibodies. Importantly, we detected a high correlation between IgG antibodies recognizing rSP03B protein and the whole salivary antigen. The kinetics of antibody response showed for both a whole saliva and rSP03B a similar pattern that was clearly related to the seasonal abundance of P. perniciosus.ConclusionsThese results suggest that P. perniciosus rSP03B protein is a valid alternative to whole saliva and could be used in large-scale serological studies. This novel method could be a practical and economically-sound tool to detect the host exposure to sand fly bites in CanL endemic areas.

Modelo de la distribución de especies vectores de leishmaniasis del género Lutzomyia (Diptera: Psychodidae) en Mérida Venezuela

Los análisis espaciales han impulsado el desarrollo de modelos que permiten predecir la distribución espacial de las especies. Con estas técnicas se estima la distribución geográfica potencial, con la representación de áreas de ocurrencia de las especies, a partir de la asociación entre los registros de presencia y las variables ambientales del sitio. El objetivo de este estudio fue evaluar la eficiencia de dos modelos, el GARP y el MaxEnt, para predecir la distribución potencial de las principales especies de Lutzomyia, en un área endémica de leishmaniasis en Venezuela. Se utilizaron 190 puntos georreferenciados en el Estado Mérida Venezuela con presencia de flebotominos. Estos puntos se dividen en 67 puntos con presencia de Lutzomyia youngi, 51 de Lutzomyia gomezi, 40 de Lutzomyia ovallesi y 32 de Lutzomyia walkeri. Las variables bioclimáticas fueron tomadas de la base de datos del Worldclim para la zona 23. Los resultados muestran que ambos modelos presentaron un buen desempeño y sus rangos de distribución son consistentes entre sí. Aunque el GARP predice una mayor distribución potencial para Lutzomyia youngi y Lutzomyia gomezi, el MaxEnt genera predicciones más ajustadas de probabilidades de ocurrencia, determinadas por las variables bioclimáticas que caracterizan la distribución potencial de cada especie. Se recomienda en mayor grado el uso del MaxEnt, porque presenta una proyección de la distribución más acorde a la contribución de las variables bioclimáticas ya que aporta datos importantes para entender la dinámica de distribución de las especies de Lutzomyia y el riesgo de transmisión de leishmaniasis en el estado Mérida, Venezuela, información relevante para los entes de control.